Re: Registax 32 bit FIT files- why don't they work in other programs?

From: Roger Hamlett (rogerspamignored_at_ttelmah.demon.co.uk)
Date: 08/21/04 

Date: Sat, 21 Aug 2004 22:23:08 GMT

> > > BSCALE = 1
> > > BZERO = 32768
> > This is the 'key' one. The offset here should be 32768, for an
unsigned
> > _16bit_ FITs file. The result as it stands, will be that the image
will
> > have 2147483648 subtracted from the effective pixel values, and then
32768
> > added!. Try changing it to 2147483648, then saving the file _as
32bit_,
> > and reopening, or try simply selecting 'process', 'pixel math', havin
just
> > one image selected, and at the bottom of the page (add constant), put
in
> > 2147450880 (2147483648-32768). You may then find the image appears OK.
> > Registax is being 'naughty', using the 32bit format as if it is
unsigned,
> > and then putting the wrong offset into here...
>
> Still couldn't get it to work, Roger, so I have abandoned any further
> workarounds. I have been down this road many times before, adding and
> subtracting values, changing historgrams, etc, and was never able to
achieve
> compatability. So, as Chris suggested, I'll just continue to stick with
the
> 16 bit FITs as they ARE compatable with most of my other images
programs.
> Thank you in earnest for your suggestions, however.
>
> Blaine
A pity.
I thought maybe I'd 'hit it' with the offset idea, but it sounds as if
something else if wrong as well.

Best Wishes